Why do I feel nervous and scared when i wake up in the morning?

Hey, I'm ah 21 year old man and for the past months I wake up feeling nervous, sometimes my heart beats racing, my stomach growling like I'm hungry. But when i get up go to work I feel good and normal. Sometimes I wake up sweating feeling nervous and doomed? I don't understand why I been dealing Gerd sing last month when i went to the doctor but it has basically gone away. Can anyone please tell me why I feel this way it's scary but when i get up I feel positive.